This invention relates generally to surge protection circuitry for protecting telephone related equipment which meets the TIA specification for Category 5. More particularly, it relates to a miniaturized Category 5 protection circuit which includes variable capacitance means connected between different sets of line-pair wires for preventing crosstalk therebetween.
In U.S. Pat. No. 5,706,160 to W. Latuszkin et al. issued on Jan. 6, 1998, and assigned to the same assignee as the present invention, there is disclosed a surge protector module 10 for protecting telecommunication equipment and the like from power and transient surges which includes a housing 12 for receiving and enclosing a printed circuit board 26. The printed circuit board 26 is disposed within the housing for mounting a plurality of circuit surge protector devices 28a-28d. This '160 patent is hereby incorporated be reference.
The printed circuit board 26 includes a tip conductive trace 62 formed on a top side thereof and a ring conductive trace 64 formed on a bottom surface thereof. The surge circuit protector device includes voltage suppressor means and diode means. The voltage suppressor means is operatively connected to the tip and ring conductive traces. The diode means is interconnected between the tip conductive trace 62 and the ring conductive trace 64 and in series with the voltage suppressor means for reducing the capacitance therebetween caused by the voltage suppressor means.
In order to meet the near end crosstalk (NEXT) criteria of the Telecommunication Industry Association (TIA) for Category 5 the distances between adjacent pairs of tip and ring conductive traces for each set of surge protector devices in the '160 patent had to be increased. However, in view of the trend of reducing the electrical component size so as to have a higher density, it was found that the conductive traces had to be spaced more closely together due to the miniaturization of the Category 5 surge protector devices. As a result, the prior art Category 5 surge protector devices became unacceptable and were found to be unable to meet the NEXT criteria because of the miniaturization.
Accordingly, it would be desirable to provide a miniaturized Category 5 protection circuit for protecting telecommunication related equipment from power and transient surges and yet still meet the NEXT criteria of the TIA specification for Category 5. This is accomplished in the present invention by adding variable capacitance means interconnected between different sets of line-pair wires so as to prevent crosstalk therebetween.